This invention relates to an automatic pipe cutting device which is generally used for cutting a metal pipe of small thickness, and particularly to an automatic pipe cutting device wherein the cutting length of the pipe is automatically adjusted by means of optical sensor and limit switch, and the fixing, cutting and discharging of the pipe is automatically achieved.
As is generally known, a metal pipe of small thickness is susceptible to modification because of its weak strength. Consequently, special attention should be paid in cutting such a metal pipe. Generally, such pipe which went through a pipe manufacturing process is cut in a predetermined length and produced on a large scale.
Typically, a scissor-type cutting roller has been used to cut a pipe. FIGS. 1 to 3 show a typical method of cutting pipe.
As shown, a typical pipe cutting device comprises a main body 100 incorporating a base plate 112 and a motor 101. An operating rod 105 supported by bearing housings 106, 107 and 108 is mounted on the base plate 112 and connected to a motor shaft 101a through pulleys 102, 103 and belts 104. Holding member 109 and guiding member 110 are fixedly mounted on the center and the front end of the operating rod 105, respectively. A fixed plate 118 is mounted on the one end of the base plate 112 and has guide rails 114 and 114' mounted thereon and at the opposite sides of the guide member 110. Each of the guide rails 116 and 114' has a carriage member 115 or 115'. A bracket 114 or 116', having a cutting roller 117 or 117' is fixed to the front face of the carriage member 115 or 115'. To the rear face of the carriage member 115 or 115' is connected a piston rod 113a or 113a' of air cylinder 113 or 113' which is fixed to the rear side of the guide rail 114 or 114'.
In normal condition in which the motor 101 is stopped, as shown in FIGS. 1 and 2, the carriage members 115 and 115' and the cutting rollers 117 and 117' are spaced at a regular distance from the guiding member 110. In this condition, a worker holds a pipe P which went through a pipe manufacturing process by both hands and insert the pipe P into the guiding member 110 for the front end of the pipe P to be caught by the holding member 109. Thereafter, at the same time as the worker removes his hands from the pipe P, he switches on operating switch of the motor 101 and air cylinders 113 and 113'. This allows the rotating force of the motor 101 to rotate the operating rod 105 through belts 104 and pulleys 102 and 103, thus rotating the holding member 109, guiding member 110 and the inserted pipe P. Consequently, the piston rods 113a and 113a' of the air cylinders 113 and 113 push the carriage members 115 and 115' causing the carriage members 115 and 115' to be moved toward the guiding member 110 along the guide rails 114 and 114'. Simultaneously with the movement, the cutting rollers 117 and 117' of the brackets 116 and 116' are moved toward the guiding member 110, thus pressing and cutting the pipe P like scissors.
In this condition, from the movement when contacting with the pipe P, the cutting rollers 117 and 117' rotate by themselves and cut the pipe P by the force of the rotation of the pipe P. The cutting length of the pipe P is the length from the tip of the cutting rollers 117 and 117' or the shoulders of the guiding members 110 and 110' to the guiding member 109. Accordingly, a worker should release a bolt 111 of the holding member 109 before entering the cutting process to adjust the location of the holding member 109 to conform with the cutting length of the pipe. After the cutting of the pipe P is finished, the motor 101 is stopped, allowing the air cylinders 113 and 113' to return the carriage members 115 and 115' and the cutting rollers 117 and 117'. Then, the worker removes the pipe P by his hands.
The feeding, supplying of the pipe P and the operation of the motor 101 and the air cylinders 113 and 113' of the above-described typical cutting device is controlled manually. Therefore, the typical device has the following disadvantages.
An accident is likely to happen because all the processes have been achieved manually. The productivity is lowered. The manufacturing cost is increased due to the excess of the labor cost. A lot of noise and vibration are produced because the operating rod 105 and the pipe P are rotated simultaneously during the cutting process.
Furthermore, since the typical cutting device is a scissors type in which the cutting rollers 117 and 117' press the periphery of the pipe P which is rotated at high speed, it can cut only the pipe of a predetermined thickness. Accordingly, a pipe of large thickness can not be cut easily, and the cutting face of the pipe gets pressed out of shape, and the cutting length is not uniform, causing the quality of the products and the reliability to lower.